Did You Know...
...that while attempting to develop a super strong glue, 3M employee Spencer Silver accidentally developed a glue that was so weak it would barely hold two pieces of paper together? However, his colleague Art Fry needed the glue. Fry sang with his church choir and marked the pages of his hymnal with small scraps of paper that often fell out. He used Silver's glue to hold the papers in place. Today we call this invention Post-it Notes.
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| Number | Title | Issue Date |
| 6111861 | Method and system for managing high speed data communication A method and device for managing the communication of high speed analog data across a communications line. If the communications line is not authorized for communication of high speed analog data, line conditioning applied (e.g., at a digital line unit or... | 08/29/2000 |
| 6111949 | Method of rapid automatic hybrid balancing The present invention provides a two-wire line conditioning apparatus having an improved calibration and cancellation circuit and provides an improved calibration method using a multitone calibration signal. The apparatus automatically adjusts an electron... | 08/29/2000 |
| 6069950 | Dual-limit current-limiting battery-feed circuit for a digital line A current-limiting circuit (110) of a battery-feed circuit (FIG. 1) for a digital telecommunications line (T,R) provides a low start-up current limit (I3) when power is initially applied to the digital line. It automatically and gradually changes (40) to ... | 05/30/2000 |
| 6041118 | Architecture for telephone set The invention concerns digital processing of analog signals in a telephone set. A signal path runs between a telephone line and the handset of the telephone. A digital signal processor is interconnected within this signal path, together with appropriate a... | 03/21/2000 |
| 5974137 | AGC amplifier for two-wire line conditioner The present invention provides a two-wire line conditioning apparatus having an improved calibration and cancellation circuit and provides an improved calibration method using a multitone calibration signal. The output is monitored by an AGC circuit which... | 10/26/1999 |
| 5963638 | Adjustable hybrid having improved biasing configuration The present invention provides a two-wire line conditioning apparatus having an improved calibration and cancellation circuit and provides an improved calibration method using a multitone calibration signal. The apparatus automatically adjusts an electron... | 10/05/1999 |
| 5963588 | Apparatus for modulating/demodulating signals An apparatus connects a data processing system (10) with an analog telephone line and/or an ISDN line. The apparatus modulates and demodulates data from the data processing system (10) to either of the two different telephone protocols without adding unne... | 10/05/1999 |
| 5953412 | Method and apparatus for controlling line conditioner equalizer The present invention provides a two-wire line conditioning apparatus having an improved calibration and cancellation circuit and provides an improved calibration method using a multitone calibration signal. The apparatus automatically adjusts an electron... | 09/14/1999 |
| 5940498 | Electronic voice circuit configuration An electronic voice circuit configuration can be connected through a first and a second line terminal to a telephone line. The electronic voice circuit configuration has a calling part, a transmitting device, a receiver device, a symmetrical modulator cir... | 08/17/1999 |
| 5912964 | Adaptive telephone handset interface An adaptive handset interface for interfacing a two-wire analog telephone instrument to a telephone set having a base unit connected to a handset via a four-wire handset cable. The interface is suitable for use with a variety of telephone sets produced by... | 06/15/1999 |
| 5901221 | Driving stage for driving differential amplifiers of a subscriber line interface circuit In a driving stage for driving the two differential amplifier output stages of a subscriber line interface circuit, the driving stage is adapted to generate four driving currents in dependence on, on the one hand, transversal and longitudinal signals inco... | 05/04/1999 |
| 5896420 | Transmission apparatus having echo cancellation facility A transmission apparatus, connected via a hybrid circuit to a line, such as a modulator-demodulator which can perform stable echo cancellation, whether the level of the far-end echo is high or not, provided with a transmission unit which generates a trans... | 04/20/1999 |
| 5887059 | System and method for performing echo cancellation in a communications network employing a mixed mode LMS adaptive balance filter A system and method for performing echo cancellation in a communications network including a bi-directional two-wire communication line, and a four-wire communication line having a transmit path and a receive path. The system includes a filter coupled to ... | 03/23/1999 |
| 5867575 | Optimized interface between audio/modem board and sound board An add-on card and connector including telephone functions is provided. The telephone functions are ones which are unlikely to be eventually performed on a mother board. A connection is provided which is adaptable to either an add-on sound card or eventua... | 02/02/1999 |
| 5854550 | Transformerless digital-line battery feed circuit A transformerless battery feed circuit for a digital telecommunications line (100) presents a high impedance to digital signals and a low impedance to direct current, and provides a constant-voltage feed with current limiting. The battery feed circuit com... | 12/29/1998 |
| 5828589 | Self-adaptive trans-hybrid balance filter An adaptive balance filter includes a transmission path, a reception path, and an adaptive filter having a signal output, a coefficient output for outputting filter coefficients, an error signal input, and a signal input coupled to the transmission path. ... | 10/27/1998 |
| 5822426 | Balanced hybrid circuit Large signal swings are obtained for the transmitted signal of a telephone line modem using differential drivers. Compensation for the complex nature of line impedance is provided without affecting the response of the receive circuits. Common-mode noise i... | 10/13/1998 |
| 5802169 | System and method for transmission system automatic impedance matching A system and method having automatic selection of impedance values for matching against unknown line impedances. The method stores an expected set of desired return loss measurements at given frequencies and matches the calculated set against the actual m... | 09/01/1998 |
| 5774541 | Optically-coupled data access arrangement and transhybrid Isolation and interconnection of a telephone network of tip and ring lines and the analog ports of a modem are achieved with a transhybrid that incorporates optically-coupled isolation stages. Optical isolators directly connect to the tip and ring lines t... | 06/30/1998 |
| 5742417 | Data access arrangement having improved transmit-receive separation A data access arrangement (DAA) having a transhybrid circuit for separating a transmit signal from a received signal by providing a transmit cancellation signal to the inverting input of a servo-feedback differential amplifier on the receive channel of th... | 04/21/1998 |
| 5734703 | Hybrid circuit and data communication apparatus The balancing bridge circuit is provided between a four-wire circuit and a two-wire circuit, to provide a thin-type balancing bridge circuit having satisfactory transmission characteristics and a MODEM and an exchange and a repeater of a telephone circuit... | 03/31/1998 |
| 5659570 | Circuit and method for loopback test and on-hook transmission integrated in a telephone subscriber line interface circuit A method and circuit for loopback testing a telephone subscriber line interface circuit (SLIC) includes current sources connected to each of tip and ring circuits from which switch-hook is detected in the SLIC. A loopback test of the SLIC is conducted whe... | 08/19/1997 |
| 5652712 | Method and apparatus for calibration of digital test equipment A processor controlled test set for testing special service circuits of a telecommunication system. A microprocessor controls the overall operation of the test set, while a digital signal processor provides high speed timing signals to the various test ci... | 07/29/1997 |
| 5636262 | Interface scanning circuit An interface scanning circuit includes a current source at the input to a multiplexer. The current source includes a transistor disposed between two resistors, the second one of which limits reverse current. Also provided are an attenuating network includ... | 06/03/1997 |
| 5623543 | Two port signalling voltages filter arrangement A twisted-pair telephone line is connected to a conventional telephone via a low-pass filter and equipment for receiving signals in an upper frequency range, e.g., 25-1000 kHz via a high-pass filter. The low-pass filter is primarily passive (to allow pass... | 04/22/1997 |
| 5602912 | Telephone hybrid circuit A method and apparatus for providing a telephone hybrid function is provided. The present invention maximizes dynamic range while providing a receive signal without interference from a transmit signal. The present invention also provides single-ended to d... | 02/11/1997 |
| 5598467 | Signal interface circuit with selectable signal interface parameters A signal interface circuit with selectable signal interface parameters for a telephone subscriber line includes an impedance circuit having a selectable impedance value, signal terminals having an associated, definable termination impedance, a transmitter... | 01/28/1997 |
| 5586181 | Metallic channel unit network A channel unit network having a two-wire port for interconnecting a two-wire, bidirectional signal transmitting means with a four-wire digital transmitting means in a communication system to create a precision bidirectional simulated two-wire cable pair w... | 12/17/1996 |
| 5579144 | Data access arrangement having improved transmit-receive separation A data access arrangement (DAA) having a transhybrid circuit for separating a transmit signal from a received signal by providing a transmit cancellation signal to the inverting input of a servo-feedback differential amplifier on the receive channel of th... | 11/26/1996 |
| 5555300 | Telephone handset microphone level adjustment A system for automatically adjusting the level of a telephone instrument microphone input signal in response to the level of the telephone instrument sidetone signal. The system may provide a test signal to the handset microphone input and receive the sid... | 09/10/1996 |
| 5555293 | Optically-coupled data access arrangement and transhybrid Isolation and interconnection of a telephone network of tip and ring lines and the analog ports of a modem are achieved with a transhybrid that incorporates optically-coupled isolation stages. Optical isolators connect to the tip and ring lines to provide... | 09/10/1996 |
| 5553137 | Method and apparatus for echo canceling in a communication system A communication system including a base station (102) and a handset (104) provides a reduced level of near end reflections which results in a reduced level of sidetone for both near end and far end users. The base station includes an echo canceler (124) t... | 09/03/1996 |
| 5546460 | Echo compensation device and 4/2-wire interface having such an echo compensation device An echo compensation device, having a digital transverse filter, for an information transmission system is described, as well as a 4/2-wire interface having at least one such device. Accordingly, a scale value device is provided which respectively evaluat... | 08/13/1996 |
| 5546421 | Self compensating spread-spectrum hybrid A communications station (10) couples a bidirectional input-output signal path (16') to two unidirectional signal paths; a transmit signal path (12') and a receive signal path (14'), using a controllable hybrid (20). A feedback control system in the stati... | 08/13/1996 |
| 5541990 | Compensated hybrid A hybrid circuit for coupling a modem to an external telephone line substantially compensates for and thereby cancels reflected echo. The hybrid includes a transformer coupled between the telephone line and the modem transceiver, which includes a transmit... | 07/30/1996 |
| 5533120 | Acoustic feedback cancellation for equalized amplifying systems A speaker amplification system incorporates an adaptable notch filter that can dynamically adapt to the frequency of feedback oscillations caused by acoustic feedback frequency in order to remove the feedback oscillation before they are amplified above an... | 07/02/1996 |
| 5526425 | Interface circuit between a four wire line and a two wire line An interface circuit between a four wire line and a two wire line includes correlator and control circuit means connected for receiving a longitudinal signal (V1) and a transversal signal (Vt) corresponding to a differential signal r... | 06/11/1996 |
| 5515433 | Resistance forward telephone line feed circuit A line feed circuit employing a low-inductance transformer, and providing a major portion of the terminating impedance as line feed resistors connected between a telephone line and the transformer primary. A low impedance output amplifier drives a low res... | 05/07/1996 |
| 5506900 | Temperature compensation for trans-hybrid loss in a miniaturized data access arrangement Method and apparatus for temperature compensation of transhybrid loss in a data access arrangement (DAA) is provided. A thermal compensation device is situated in proximity to a thermally sensitive device. If devices which dissipate substantial power caus... | 04/09/1996 |
| 5500892 | Echo canceller Analog signals representing individual digital values (+3, +1, -1, -3) of data pass through a telephone line to a receiver. These signals may first be provided in a pseudo random sequence. A linear echo canceller and a first adder at the receiver simultan... | 03/19/1996 |
